Catalyst In Situ Generated Sio <sub> 2 </ Sub> Structure Of The Particles And (peo) <sub> 8 </ Sub> Of Liclo <sub> 4 </ Sub>-sio <sub> 2 </ Sub> Composite Things Membrane Performance

Firstly, in order to understand the effects of the process of SiO₂ particle growth, taking ethyl-orthosilicate (TEOS) as the precursor, SiO₂ sol, PEO/SiO₂ and (PEO)₈LiClO₄-SiO₂ were prepared by blending in-situ. And the influences of polymer, lithium salt, catalyst in the process of SiO₂ particle growth were inspected. The growth of the nanometer particle SiO₂ were studied by Ultraviolet-Visible light spectrophotometer, transmission electron microscope (TEM), atom force microscopy(AFM). Secondly, we studied the effects of structure of SiO₂ in the properties of (PEO)₈LiClO₄-SiO₂ composites. (PEO)₈LiClO₄-SiO₂ composites were prepared by blending in situ, which ethyl-orthosilicate (TEOS) was catalyzed both by HCl and NH₄OH. The crystallinity and ionic conductivity of the CSPE were investigated by different scanning calorimeter(DSC), X-Ray diffracts (XRD) and A.C.impedance spectroscopy. The gas sensitivity and the surface properties of (PEO)₈LiClO₄-SiO₂ composites were studied too.The results of Ultraviolet-Visible light spectrophotometer show that the acid-catalyzed SiO₂ sol is stabler than the alkali-catalyzed SiO₂ sol. The acid-catalyzed SiO₂ sol. The results of TEM show that under the SiO₂ sol system, the size of SiO₂ particle is approximately 35nm, the shape is not really regular, particles agglomerate partly and size distribute widely. Under PEO/SiO₂ system, PEO surround the SiO₂ particle formed core-shell structure, the average particle size is about 100nm.Under the (PEO)₈LiClO₄-SiO₂ system, the results of AFM show that SiO₂ particles in the acid-catalyzed (PEO)₈LiClO₄-SiO₂ film surface results are not so protuberant as SiO₂ particles in the acid-catalyzed (PEO)₈LiClO₄-SiO₂ film surface. The height of SiO₂ in acid-catalyzed (PEO)₈LiClO₄-SiO₂ film is 18.8nm; the height of SiO₂ in alkali-catalyzed (PEO)₈LiClO₄-SiO₂ film is 80.5nm. The results of TEM show that both alkali-catalyzed SiO₂ particles and alkali-catalyzed SiO₂ particles with the sizes of 50～100nm were quite well dispersed in the CSPE. The figure of alkali-SiO₂ particles was round and the interfaces were conspicuous. The figure of acid-catalyzed SiO₂ particles was not regular and the interfaces were unconspicuous. Both the results of AFM and TEM indicate the compatibility of acid- catalyzed SiO₂ in CSPE is better than alkalicatalyzed SiO₂.DSC and XRD show that the crystallinity of acid-catalyzed (PEO)₈LiClO₄-SiO₂ and alkali-catalyzed (PEO)₈LiClO₄-SiO₂ are 8.6% and 10.2 % respectively. The crystallinity is observed to decrease greatly by addition of modified SiO₂. A. C. impedance spectra of CSPE shows that the conductivity is increased obviously by addition of SiO₂ at room temperature. When SiO₂ concentration is at about 10wt%, the conductivity of alkali-catalyzed CSPE and acid-catalyzed CSPE attains the maximum value. The conductivity of alkali-catalyzed CSPE and acid-catalyzed CSPE are 1.1×10^-5 S·cm^-1 and 2.2×10^-5 S·cm^-1 respectively at 30℃. The gas sensitivity testing show that the responsive resistance of acid-catalyzed (PEO)₈LiClO₄-SiO₂ is 717.1KΩin air and 508.1KΩin ethanol; the responsive resistance of alkali-catalyzed (PEO)₈LiClO₄-SiO₂ is 2792. 1KΩin air and 796.6KΩin ethanol. The smaller the bulk resistance is, the bigger the conductivity is. The conductivity of acid-catalyzed (PEO)₈LiClO₄-SiO₂ is bigger than alkali-catalyzed (PEO)₈LiClO₄-SiO₂ which is consistent with the results of A. C. impedance spectra. The results of contact angle testing show that the ionic conductivity is related to the surface flee energy, the smaller the surface free energy is, the bigger the ionic conductivity is; the bigger the surface free energy is, the smaller the ionic conductivity is.